Switched-mode power amplifier integrally performing power combining

ABSTRACT

A switched-mode power amplifier is configured for performing power amplification of a plurality of signals input thereto and integrally summing (combining) those signals. Conceptually, this is achieved by replacing the input winding of the transformer component of a transformer-coupled voltage switching amplifier with separate input components, one for each input signal, in similar manner to the configuration of the input components of a three-port combiner (trifilar). In a first transformer-containing category of embodiments of the invention, the input winding of the amplifier&#39;s transformer is comprised of a plurality of series-coupled windings, one for each of the plurality of input components/signals such that the input components constitute a series connection of low output impedance sources applied to the amplifier&#39;s resonator and load. This, in turn, provides a high level of isolation between the amplifier input components and results in a low level of loss. In a second non-transformer-containing category of embodiments of the invention, the transformer component is replaced by a transmission line impedance transformer, or a lumped element equivalent circuit, which transforms the low output impedance sources to high output impedance sources and those sources are connected in parallel (rather than in series per the first category of embodiments).

RELATED APPLICATION

This application is a continuation-in-part application of applicationSer. No. 10/004,703 filed on 3 Dec. 2001 now U.S. Pat. No. 6,603,352.

FIELD OF THE INVENTION

The invention relates to circuitry for radio frequency (i.e. “RF” or“wireless”) transmitters and in particular to power amplifier circuitryproviding signal combining integral to the power amplification.

BACKGROUND OF THE INVENTION

Typically, power combiners are used in RF transmitters to combine theoutput signals of parallel power amplifiers into one high power RFoutput signal for wireless transmission. In these known transmitterstructures the signals are first amplified by the power amplifiers andthen they are combined by a power combiner to produce a combinedamplified signal for transmission. Depending upon the circuitarchitecture and signal format used, however, it becomes necessary tomake trade-offs between reducing power losses and achieving isolationbetween input signals of the combiner.

The need for efficiency is a particularly important design factor forthe highly integrated requirements of transceivers used for wirelesslocal area networks (LANs) and employing modulation formats such as OFDM(Orthogonal Frequency Division Multiplex). Moreover, the assignee ofthis invention and application has developed signal modulation methods,using OFDM signal format, whereby information signals are deconstructedinto independent component signals, these independent signals being moreefficiently processed and modulated than the original informationsignals from which they derive, and then the independent signals areup-converted, amplified and combined prior to transmission. Use of suchindependent modulated signals presents additional challenges toachieving efficiency at the amplification/combination stages of thetransmitter, however, because the conventional model of amplificationfollowed by combining, using known power amplifiers and combiners, issubject to inherent loss and isolation limitations.

Non-reciprocal combiners are considered to be non-economic forapplications such as low cost wireless. Instead, reciprocal combiners,realized as either four-port or three-port structures, are available foruse in such applications. Four-port combiners provide an advantage ofisolation between the individual inputs (which means that the outputimpedances of the amplifier stages do not load each other) but where thesignals being amplified are non-identical (i.e. statisticallyindependent) an inherent loss of 3 dB results (this loss disappearswhere the signals are identical due to resonance). Thus, four-portcombiners are generally only suitable for use where the signals beingamplified are identical.

A three-port combiner, also known as a trifilar, is able to provide adegree of isolation between its individual inputs, depending upon theoutput impedance of the amplifiers feeding it and the load impedanceconnected to the combiner's output. If the output impedances of theindividual amplifiers and the output loading impedance of the combinerare the same, then isolation is not achieved and an inherent loss of 3dB results. On the other hand, if the output impedances of theamplifiers are small in comparison with the output loading impedance ofthe combiner, then the inherent loss diminishes, and approaches 0 dB for0 ohms output impedance.

The many classes of power amplifiers can be broadly sorted into twoclassifications; linear and switched-mode. Linear amplifiers provide anoutput-impedance resulting from the bias condition and load line for theactive device (in the usual case, the active device being a transistor).In practice, this output impedance is typically in the range of 5 to 50ohms. As a result, limited isolation is achievable when using athree-port combiner (trifilars) to combine the outputs of two linearamplifiers. As known by persons skilled in the art, a conventional classD, E or F switched-mode power amplifier consists of an input componenthaving at least one active (switching) device, a central transformercomponent and an output component consisting of a resonator. It isimpractical to apply the output signals of separate switched-modeamplifiers to a trifilar, to combine them, because of the cost and spacerequirements (and resulting inefficiency) associated with the multipletransformer windings required for such a design.

By reason of the foregoing limitations of known RF components, thereexists a need for new and efficient means to achieve power amplificationand combining of modulated signals in transmitters.

SUMMARY OF THE INVENTION

As disclosed in the parent application Ser. No. 10/004,703, aswitched-mode power amplifier is configured for performing poweramplification of a plurality of analog, phase-modulated signals inputthereto and integrally combining those signals. Conceptually, this isachieved by replacing the input winding component(s) of the transformerwithin a conventional transformer-coupled voltage switching amplifierwith separate input winding components, one for each input signal, insimilar manner to the configuration of the input components of aconventional three-port combiner (trifilar). Accordingly, the inputwinding of the amplifier's transformer is comprised of a plurality ofseparate, series-coupled input component windings.

The inventors have found that the foregoing series-coupled inputcomponent windings, representing voltage sources of low outputimpedance, and output winding, can be replaced by a suitable impedanceinverter so as that instead of representing low output impedance voltagesources they represent high output impedance current sources.Accordingly, in accordance with the present invention there is providedan alternative, parallel-coupled, switched-mode power amplifierconfigured for integrally amplifying and combining a plurality ofsignals (e.g. analog phase modulated signals) input thereto. Theamplifier comprises an input component for each of the plurality ofinput signals. Each input component comprises at least one active deviceconfigured to be alternately switched by the input signal and to presentan amplified signal corresponding to the input signal, such that eachinput component constitutes a low output impedance voltage source. Anoutput resonator component connects to a load and an impedance inverteris provided between each input component and the resonator component.The impedance inverter is configured for transforming the low outputimpedance voltage source to a high output impedance current source sothat the high output impedance sources produced by the input componentscan be combined in parallel, to produce a summation signal, before beingpassed to the resonator component.

The amplifier may be class D, E or F and may be a balanced orunbalanced-type amplifier. The impedance inverter may be aquarter-wavelength transmission line or a lumped element equivalentcomponent, for example, comprising a series inductor and twoshunt-to-ground, negative inductors of equal absolute value connected toeach terminal end of the series inductance. In a semiconductor productimplementation of the amplifier it is advantageous to incorporate thenegative inductors into other reactive components of the amplifier.Moreover, in such implementation the series inductor may be provided bya spiral inductor as known in the art. However, as disclosed in aco-pending application assigned to the same assignee as thisapplication, entitled “Integrated Circuit Incorporating Wire BondInductance” and filed on the same date as this continuation-in-partapplication, the content of which is incorporated herein by reference,the series inductor may instead be provided by means of a wire-bond(which takes advantage of an inherent, but heretofore undesirableproperty of wire-bonds).

In accordance with a further aspect of the invention there is provided amethod for integrally amplifying and combining a plurality of inputsignals to produce a single amplified, summation signal for input to aresonator component. Each input signal is amplified by a separateamplifier input component to produce an amplified signal correspondingto the input signal and constituting a low output impedance voltagesource. To perform the amplifying the input signal is applied to atleast one active device of the input component to cause alternateswitching of the active device. Each low output impedance voltage sourceis transformed to a high output impedance current source and the highoutput impedance sources are combined, in parallel, to produce thesingle amplified, summation signal.

The transforming is performed by a quarter-wavelength transmission lineimpedance inverter or lumped element equivalent component, for example,a series inductor and two shunt-to-ground, negative inductors of equalabsolute value connected to each terminal end of the series inductance.Preferably, the negative inductors of the lumped element equivalentcomponent are incorporated into other reactive components and the seriesinductor of the lumped element equivalent component is provided by meansof a spiral inductor or wire-bond in a semiconductor product configuredto implement this method.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary preferred embodiments of the invention, and variants thereof,are described in detail below with reference to the following drawingsin which like references refer to like elements throughout:

FIG. 1 illustrates a prior art balanced, transformer coupled,switched-mode power amplifier (class D) having a voltage switchingarchitecture, as well known to persons skilled in the art;

FIG. 2 illustrates a prior art three-port power combiner (also referredto as a “trifilar”), as well known to person skilled in the art;

FIGS. 3A(i), 3A(ii) and 3B illustrate switched-mode power amplifiersconfigured in accordance with the present invention for performingintegral combining and amplification of the input signals (shown here asthe two input signals Vin1 and Vin2);

FIG. 3A(i) illustrates a balanced switched-mode power amplifier forperforming integral combining in accordance with the invention, whereinone half of the center-tapped winding of each input component of theamplifier is used for each half cycle of the signal input thereto (Vin1and Vin2);

FIG. 3A(ii) illustrates a variant configuration of a balancedswitched-mode power amplifier which differs from the design shown byFIG. 3A(i) in that the full winding of each input component of theamplifier is used for each half cycle of the signal input thereto (Vin1and Vin2) i.e. instead of the center-tapped (i.e. half) windings of theembodiment shown by FIG. 3A(i);

FIG. 3B illustrates an unbalanced class F switched-mode power amplifierconfigured for performing integral combining of the signals inputthereto (Vin1 and Vin2) (but, as will be noted by a person skilled inthe art, this circuit omits the use of a parallel resonant circuit, inseries before the load, tuned to the third harmonic, to support thethird harmonic voltages);

FIG. 4 illustrates the well-known, prior art Wilkinson combiner circuitconfiguration which provides a transmission line equivalent to thetrifilar, with an isolating resister between the separate inputs,wherein the separate inputs are combined in series by means of theimpedance inversion operation of a quarter-wavelength (λ/4) transmissionline, as shown;

FIG. 5 illustrates a transmission line equivalent to the trifilarconfigured for incorporation into a switched-mode amplifier to achieveintegral combining in accordance with the invention;

FIG. 6 illustrates a variant configuration of the unbalancedswitched-mode power amplifier of FIG. 3B, for performing integralcombining of the signals input thereto (Vin1 and Vin2) using atransmission line equivalent to the trifilar, per that FIG. 5, insteadof the trifilar shown in FIG. 3B;

FIGS. 7A, 7B, 7C and 7D illustrate four different, alternative lumpedelement circuit equivalents to quarter-wavelength transmission linesand, therefore, these also provide circuit equivalents for the trifilar;and,

FIG. 8 illustrates a further variant configuration of the unbalancedswitched-mode power amplifier of FIG. 3B, for performing integralcombining of the signals input thereto (Vin1 and Vin2) using a lumpedelement equivalent to the trifilar, per that FIG. 7A, instead of thetrifilar shown in FIG. 3B.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Surprisingly, the inventor(s) invented and developed a means forachieving improved power amplification and power combining whichprovides greater efficiency over the known, successively staged poweramplifier and combiner designs. Advantageously, the switched-modeamplifier of the present invention integrally performs poweramplification and combining of signals input thereto. According to theinvention multiple input signals are combined (summed) inside the poweramplifier after they are amplified and before they are applied to theresonator component of the amplifier, and hence to a load impedance.This contrasts markedly with the known power amplifiers for which powercombining takes place following the complete amplification process. Aknown (prior art) switched-mode power amplifier is illustrated by FIG. 1and a known (prior art) three-port power combiner (trifilar) isillustrated by FIG. 2, the configuration, manner of operation, andoperating parameters and characteristics of both of these devices beingwell understood by persons skilled in the art.

The prior art switched-mode power amplifier shown by FIG. 1 has atransformer-coupled voltage switching architecture and comprises abalanced center-tapped input winding 30 made up of input windingcomponents 10, 20 and an output winding 40 which, together, make up atransformer component of the amplifier. The manner of operation of thisamplifier is well known by persons skilled in the art. In operation, theoutputs of the active devices (transistors) 16, 18 function as ateeter-totter switch, switching between the two input peak levels of thesignals Vin and Vin′ 12, 14, where Vin′ is the inverse of Vin (Vin beinga constant envelope phase modulated signal). The resulting signalsproduced by each input winding component 10 and 20 track the phasechanges of the input signal Vin and alternately switch between a voltagerail V_(DD) and ground. Therefore, the signals at winding components 10and 20 are two complementary square wave voltage signals which arecombined by the input winding 30 to produce an amplified signalcorresponding to the input signal Vin. The half windings are balancedand have a high coupling coefficient between them, for purposes ofefficiency. The amplified summation signal which results across theoutput winding 40 of the transformer component is connected in series toa tuned output resonator (filter) component, comprising an inductor (L)50 and capacitor (C) 60, for output to a load impedance (R) 78.

The active devices 16 and 18 of the foregoing switched-mode amplifiernever experience, simultaneously, a voltage across them and a currentthrough them. Consequently, they present an output impedance thatalternates between an open circuit and a short circuit. The outputimpedance for each individual active device is complementary to that ofthe other active device in that when one is an open circuit, the otheris a short circuit. When an open circuit is presented to one component,10 or 20, of the input winding 30 it does not load the transformer(since no current will flow through that particular input windingcomponent 10 or 20) and the resulting composite impedance presented tothe transformer is that of the short circuit (zero ohms) from thecomplementary input winding component 20 or 10, respectively. Note thatthis exemplary switched-mode amplifier uses voltage switching. Analternative to voltage switching is to use current switching whichswitches between a current source and an open circuit. However, inpractice such alternative may be less desirable due to the need toprovide a constant current source.

The inventor(s) discovered that this very low (theoretically zero)output impedance presented by the active devices 16, 18 of aswitched-mode amplifier can be used advantageously to achieve asuperposition i.e. combining of signal voltages. Specifically, theinventor(s) made a surprising discovery that such a superposition ofvoltage signals is achieved by replacing the center-tapped transformerof this switched-mode power amplifier with separate input stages insimilar manner to a three-port combiner (trifilar).

An illustration of one embodiment of the invention is provided by FIG.3A(i) from which it can be seen that the input winding 30 (consisting ofwinding halves 10 and 20) of the transformer of the prior art amplifierillustrated by FIG. 1 has been replaced, in this switched-modeamplifier, by input windings 72 and 74 of separate input components 70and 80, one for each of two input voltage signals Vin1 and Vin2 whichare to be amplified and combined, wherein the input components 70, 80comprise active devices 82 and 84, and 86 and 88, resp., and the inputwindings 72 and 74, resp. As such, each input component 70, 80 functionsin similar manner to one trifilar input.

As shown by FIG. 3A(i), the signals Vin1, Vin1′ and Vin2, Vin2′ are fedto the active devices 82, 84 and 86, 88, respectively (whereby Vin1′ isthe inverse of Vin1 and Vin2′ is the inverse of Vin2). Windings 72 and74 see only the very low impedance (theoretically zero) of the activedevice which drives them (i.e. the active device which is switched onand presents a short circuit). The two input component windings 72 and74 are coupled in series and, by superposition, the current waveformsgenerated within these windings by the two input voltage signals Vin1and Vin2 are caused to superimpose and result in a summation of the twosignals within the output winding 44 which is connected at one terminalend to ground and at the other terminal end to a resonator component 50,60. This summation occurs within the amplifier before the amplified,summed signal is fed to the resonator component 50, 60 and hence to aload impedance 78. As such, a single amplifier resonator is sharedbetween the two switched-mode amplifier input signals Vin1 and Vin2.Alternatively, in a different (optional) embodiment (not shown) bothterminal ends of the output winding 44 may be connected to a resonatorcomponent in a balanced manner (instead of one terminal end beingconnected to ground as illustrated in FIG. 3A(i)).

The integrally combining amplifier of FIGS. 3A(i) and 3A(ii) achievessuch combining of non-identical (independent) input signals Vin1 andVin2 with low (theoretically zero) loss. It is to be understood that,although this illustrated embodiment uses only two input signals (Vin1and Vin2, being analog, constant envelope phase modulated signals) alarger number of input signals (i.e. Vin1, Vin2, Vin3, . . . ) may beamplified in similar manner in accordance with the invention.

FIG. 3A(ii) illustrates a variant circuit design to that shown by FIG.3A(i) wherein a bridge architecture is used for the amplifier inputcomponents 100 and 110 rather than the balanced architecture of theembodiment of FIG. 3A(i). In this embodiment the full input componentwinding 140, 150 of each input component 100 and 110, respectively, isused for each switched cycle of the signal input thereto (Vin1 andVin2). This differs from the balanced architecture of the embodiment ofFIG. 3A(i) in which half windings, only, are energized at any given timeand, thus, the half windings must be highly coupled. As shown, for eachinput component 100 and 110 bridge-configured (i.e. cross-located) pairsof active devices (transistors) 112 and 118, 114 and 116 and 120 and126, 122 and 124, respectively, are alternately switched between an opencircuit and a short circuit. As a result, the direction of current flowthrough each of the windings 140, 150 is alternately switched every halfcycle of the signal and the full winding is used each time. Therefore,this embodiment avoids the need to ensure highly coupled half windingsassociated with the embodiment of FIG. 3A(i).

FIG. 3B illustrates a further embodiment of an amplifier circuit designconfigured according to the present invention to perform integralcombining. This figure illustrates an unbalanced class F amplifierarchitecture but omits use of a parallel resonant circuit tuned to thethird harmonic, to support the third harmonic voltages, as is commonlyincluded in series before the load (such omission having a relativelyminor effect on the overall performance/efficiency of an actual,practical amplifier circuit since the third harmonic signals are of muchlesser significance than the fundamental or second harmonic signals).The configuration, operating parameters and characteristics of thisamplifier architecture are well-known by persons skilled in the art.

A Class F amplifier is designed to provide a good approximation to avoltage square-wave across the output terminals of the active device. Intheory it does so by “shorting” all even-harmonic voltages and“supporting” all odd-harmonic voltages, but in practice it is typical toprocess only the second harmonic voltage, or only the second and thirdharmonic voltages, accordingly. As a result, the voltage waveform acrossthe output terminals of the active device contains only odd-harmoniccomponents. In addition, this sorting of odd- and even-harmonics, whichmay be conveniently achieved (up to the third harmonic) with a seriesresonant circuit (at the second harmonic) connected across the activedevice's output terminals, and a parallel resonant circuit (at the thirdharmonic) connected between the active device's output terminal and theload, results in a current passing through the output terminals of theactive device that contains the fundamental, and only even-harmoniccomponents. The series resonator (consisting of L(2f) 270 and C(2f) 280for the Vin1 signal input component and L(2f) 272 and C(2f) 282 for theVin2 signal input component in the circuit of FIG. 3B) will short thesecond harmonic signal and support the third harmonic signal, while theparallel resonator will block the third harmonic signal from the load.Since each harmonic contains only a voltage component or a currentcomponent, the active device will not absorb power, except at thefundamental frequency. A problem associated with the Class Farchitecture, however, is the existence of a source-drain(emitter-collector) parasitic capacitance which detunes the resonanceswhich, in practice, allows some amplitude of all harmonics of thevoltage and current to exist.

As shown by FIG. 3B, the separate input signals Vin1 and Vin2 are inputto active devices 200 and 210 which switch between the voltage rail(V_(DD)) and ground depending on the input signal value. As for theprevious embodiments, the input signals are thereby amplified andcombined, by means of coupled input windings 220 and 230 and the outputwinding 240, before being passed to a resonator component 250, 260designed to pass the current of the fundamental frequency to the load.

Surprisingly, the inventor(s) found that the functionality of the inputand output windings (i.e. the transformer component) of the foregoingamplifier circuit designs may be achieved, in equivalent manner, throughthe use of various equivalent (alternative) components located eitherdirectly within the circuit itself or indirectly external to the circuitbut electronically within it, as detailed hereinafter. Advantageously,these equivalent components do not use a magnetic transformer and, thus,avoid the inherent significant loss which results from a magnetictransformer due the limited Q that can be achieved for coils on asemiconductor substrate.

In making this finding, the inventor(s) initially contemplated thewell-known Wilkinson combiner circuit configuration shown by FIG. 4,which provides a transmission line equivalent to the trifilar. As shownin FIG. 4, an isolating resister (R) is provided between separate inputs(Input 1 and Input 2) and these inputs are combined in series by meansof an impedance inversion operation resulting from the use of aquarter-wavelength (λ/4) transmission line i.e. a transmission linewhose length is equal to one quarter of the wavelength of the inputsignals. This is also referred to as an impedance inverter whichfunctions to transform a low output impedance to a high outputimpedance. As is known by persons skilled in the art (and shown by FIG.4), the characteristic impedance of such a transmission line is 1.414(i.e. 2^(1/2)) times the impedance of the input components (Input 1 andInput 2) to achieve matching to the output impedance.

FIG. 5 schematically illustrates a transmission line equivalent to thetrifilar for incorporation into an unbalanced switched-mode amplifier toperform integral combining of the signals input thereto (Vin1 and Vin2).FIG. 6 illustrates an unbalanced switched-mode amplifier in which aquarter-wavelength (λ/4) transmission line 300 is used accordingly.

Next, it was contemplated by the inventor(s) that the impedance inverterfunction provided by the foregoing transmission line equivalent, is alsoprovided by the lumped element equivalent circuit shown by FIG. 7Aconsisting of a series inductance and two shunt-to-ground, negativeinductances of equal absolute value connected to each terminal endthereof. Similarly, the lumped element equivalents shown by FIGS. 7B, 7Cand 7D provide the same impedance inverter function (since, over alimited bandwidth, a positive capacitor will function equivalently to anegative inductor).

FIG. 8 illustrates an embodiment of the invention which uses, forintegral combining, lumped element equivalent components (impedanceinverters) 400, 410, according to that shown by FIG. 7A, in place of thetrifilar-type transformer component of the foregoing unbalancedswitched-mode power amplifier shown in FIG. 3B. It has been found,advantageously, that the negative inductances may be realized byincorporating their values into other existing reactive circuit elementssurrounding the active device such as adjacent harmonic traps, RF chokesand the output resonator. Alternatively, they may be realized over alimited bandwidth with the use of a positive capacitor (and, similarly,a negative capacitor may be realized with the use of a positiveinductor).

For the particular amplifier circuit design shown in FIG. 8, theleft-most negative inductance of the impedance inverter is realized byincorporating its value into the second harmonic resonator (trap) orbias inductor and the right-most negative inductance is taken intoaccount by appropriate changes in the values of the inductor andcapacitor of the following resonator circuit. Moreover, it has beendetermined by the assignee of this invention that the positiveinductance of the impedance inverter can be realized as a wire-bond inthe semiconductor product implementation of the circuit, whereby theactual combining takes place off die, at the package pin. The means andmethod of performing such a wire-bond realization is described in detailin a co-pending application assigned to the same assignee as thisapplication, entitled “Integrated Circuit Incorporating Wire BondInductance” and filed on the same date as this continuation-in-partapplication, which is incorporated herein by reference.

The individual electronic and processing functions utilised in theforegoing described embodiment are, individually, well understood bythose skilled in the art. It is to be understood by the reader that avariety of other implementations may be devised by skilled persons forsubstitution. Moreover, it will be readily understood by persons skilledin the art that a coil (inductor) component such as item 44 shown inFIG. 3A(i) can be provided by an equivalent plurality of smallerseries-connected coils (i.e. rather than a unitary coil). The claimedinvention herein is intended to encompass all such alternativeimplementations, substitutions and equivalents. Persons skilled in thefield of electronic and communication design will be readily able toapply the present invention to an appropriate implementation for a givenapplication.

Consequently, it is to be understood that the particular embodimentsshown and described herein by way of illustration are not intended tolimit the scope of the invention claimed by the inventors/assignee whichis defined by the appended claims.

1. A switched-mode power amplifier configured for integrally amplifyingand combining a plurality of analog phase modulated signals inputthereto, said amplifier comprising: (a) an input component for each ofsaid plurality of analog phase modulated input signals wherein each saidinput component comprises at least one active device configured to bealternately switched by-said by an analog phase modulated input signalto present an amplified signal corresponding to said analog phasemodulated input signal, said amplified signal constituting a low outputimpedance voltage source; (b) an output resonator component; and, (c) animpedance inverter between each said input component and said resonatorcomponent, said impedance inverter configured for transforming said lowoutput impedance voltage source to a high output impedance currentsource, wherein said high output impedance sources are combined inparallel before being passed to said resonator component; wherein saidimpedance inverter comprises a lumped element equivalent component to aquarter-wavelength transmission line: wherein said lumped elementequivalent component comprises two or more of a series inductor, aseries negative inductor, a shunt-to-ground inductor, a shunt-to-groundnegative inductor, a series capacitor, a series negative capacitor, ashunt-to-ground capacitor, and a shunt-to-ground negative capacitor. 2.A switched-mode power amplifier according claim 1, wherein said lumpedelement equivalent component comprises a series inductor and twoshunt-to-ground, negative inductors connected to each terminal end ofsaid series inductor, said inductors being of equal absolute value.
 3. Aswitched-mode power amplifier according to claim 1, wherein said lumpedelement equivalent component comprises two series negative inductors anda shunt-to-ground inductor between said series inductor, said inductorsbeing of equal absolute value.
 4. A switched-mode power amplifieraccording to claim 1, wherein said lumped element equivalent componentcomprises a series capacitor and two shunt-to-ground, negativecapacitors connected to each terminal end of said series capacitor, saidcapacitors being of equal absolute value.
 5. A switched-mode poweramplifier according to claim 1, wherein said lumped element equivalentcomponent comprises two series negative capacitors and a shunt-to-groundcapacitor between said series capacitor, said capacitors being of equalabsolute value.
 6. A method for integrally amplifying and combining aplurality of analog phase modulated input signals to produce a singleamplified, summation signal for input to a resonator component, saidmethod comprising: a. amplifying each said analog phase modulated inputsignal by a separate amplifier input component to produce an amplifiedsignal corresponding to an analog phase modulated input signal andconstituting a low output impedance voltage source, said amplifyingcomprising applying said analog phase modulated input signal to at leastone active device of said input component to cause alternate switchingof said active device; and, b. transforming each said low outputimpedance voltage source to a high output impedance current source; and,c. combining said high output impedance sources in parallel to produce asingle amplified, summation signal; wherein said transforming isperformed by an impedance inverter comprising a lumped elementequivalent component to a quarter-wavelength transmission line; andwherein said lumped element equivalent component comprises two or moreof a series inductor, a series negative inductor, a shunt-to-groundinductor, a shunt-to-around negative inductor, a series capacitor, aseries negative capacitor, a shunt-to-ground capacitor, and ashunt-to-around negative capacitor.
 7. A method according to claim 6,whereby said lumped element equivalent component comprises a seriesinductor and two shunt-to-ground, negative inductors of equal absolutevalue connected to each terminal end of said series inductance.
 8. Amethod according to claim 6, whereby said lumped element equivalentcomponent comprises two series negative inductors and a shunt-to-groundinductor between said series inductor, said inductors being of equalabsolute value.
 9. A method according to claim 6, whereby said lumpedelement equivalent component comprises a series capacitor and twoshunt-to-ground, negative capacitors connected to each terminal end ofsaid series capacitor, said capacitors being of equal absolute value.10. A method according to claim 6, whereby said lumped elementequivalent component comprises two series negative capacitors and ashunt-to-ground capacitor between said series capacitor, said capacitorsbeing of equal absolute value.
 11. A switched-mode power amplifierconfigured for integrally amplifying and combining a plurality ofsignals input thereto, said amplifier comprising: (a) an input componentfor each of said plurality of input signals wherein each said inputcomponent comprises at least one active device configured to bealternately switched by said input signal to present an amplified signalcorresponding to said input signal, said amplified signal constituting alow output impedance voltage source; (d) an output resonator component;and, (e) an impedance inverter between each said input component andsaid resonator component, said impedance inverter configured fortransforming said low output impedance voltage source to a high outputimpedance current source, wherein said high output impedance sources arecombined in parallel before being passed to said resonator component;wherein said impedance inverter comprises at least one of: (i) a seriesinductor and two shunt-to-ground, negative inductors connected to eachterminal end of said series inductor, said inductors being of equalabsolute value; (iii) two series negative inductors and ashunt-to-ground inductor between said series inductor, said inductorsbeing of equal absolute value; (ii) a series capacitor and twoshunt-to-ground, negative capacitors connected to each terminal end ofsaid series capacitor, said capacitors being of equal absolute value;and (iv) two series negative capacitors and a shunt-to-ground capacitorbetween said series capacitor, said capacitors being of equal absolutevalue.